Index: hook.rb
===================================================================
--- hook.rb	(Revision 3450)
+++ hook.rb	(Arbeitskopie)
@@ -57,12 +57,7 @@
       # Calls a hook.
       # Returns the listeners response.
       def call_hook(hook, context={})
-        returning [] do |response|
-          hls = hook_listeners(hook)
-          if hls.any?
-            hls.each {|listener| response << listener.send(hook, context)}
-          end
-        end
+        hook_listeners(hook).map {|listener| listener.send(hook, context)}
       end
     end
 
@@ -110,9 +105,22 @@
       #
       def self.render_on(hook, options={})
         define_method hook do |context|
-          context[:controller].send(:render_to_string, {:locals => context}.merge(options))
+          if !options.include?(:if) || evaluate_if_option(options[:if], context)
+            context[:controller].send(:render_to_string, {:locals => context}.merge(options))
+          end
         end
       end
+
+      private
+
+      def evaluate_if_option(if_option, context)
+        case if_option
+        when Symbol
+          send(if_option, context)
+        when Method, Proc
+          if_option.call(context)
+        end        
+      end
     end
 
     # Helper module included in ApplicationHelper and ActionControllerso that
@@ -145,8 +153,16 @@
         end        
       end
     end
+
+    module ActionMailerMethods
+      def render_to_string(options={})
+        ActionView::Base.new(ActionController::Base.view_paths.dup, {}, self).render(options)
+      end
+    end
   end
 end
 
 ApplicationHelper.send(:include, Redmine::Hook::Helper)
 ActionController::Base.send(:include, Redmine::Hook::Helper)
+ActionMailer::Base.send(:include, Redmine::Hook::ActionMailerMethods)
+ActionView::Base.send(:include, Redmine::I18n)